Waterproof watch crown



Margh 12, 1957 J. WALDMAN WATERPROOF WATCH CROWN Filed Sept. 14, 1954 IN V EN TOR.

W W W/j United States Patent WATERPROOF WATCH CROWN Joseph Waldman, Maplewood, N. J., assignor to Joseph Waldman & Sons, Irvington, N. J., a firm Application September 14, 1954, Serial No. 455,908

1 Claim. (CI. 58-90) This invention relates to watch crowns, and has reference, more particularly, to a crown having improved means to provide a waterproof seal between the crown and the watch case served thereby.

Attempts have heretofore been made to render a watch crown waterproof when operatively assembled with a watch case and the contained watch works, i. e., sealed against admission of moisture between the crown and the neck of the watch case about which the crown can be rotated to actuate a winding and setting stem to which the crown is attached. The construction ordinarily heretofore provided for this purpose has comprised a compressible resilient sealing element disposed to surround and engage the watch case neck intermediate the latter and the skirt wall of the crown body, whereby to cause said element, under the tension thereof induced by its compression, to press radially against the external surface of the watch case neck. Such compressed resilient seals have not been found to be satisfactory since, under compression strong enough to assure tight sealing effect, considerable friction is developed between the seal element and the watch case neck which resists rotation of the crown relative to said neck, and thus not only renders manual winding and setting rotation of the crown unduly difficult, but causes rapid wear of the seal element with risk of impairment of its sealing effect. To avoid such undesirable conditions, attempts have also been made to provide means for adjusting or regulating the amount of compression imposed upon the seal element and resultant friction. Such means adds considerably to the complication and cost of the crown structure, and has not proven to be a satisfactory solution, since, if compression of the seal element is reduced to substantially lessen friction, risk of loss of sealing efiect arises.

Having the above in view, it is an object of this invention to provide, in combination with a watch crown, an improved form and mounting of sealing element which, when the crown is operatively related to the neck of a watch case, provides a sealing portion that bears against and hugs said neck in a resiliently yieldable manner, so that friction between these parts is reduced to minimum, and yet efficient sealing effect against moisture admission is assured.

The above and other objects will be understood from a reading of the following detailed description of this invention in connection with the accompanying drawings, in which:

Fig. l is a transverse vertical sectional view of a watch crown provided with a waterproofing seal element according to this invention operative to seal against the neck of a watch case; Fig. 2 is a similar view, but showing the seal element in elevation; Fig. 3 is a horizontal sectional View, taken on line 3-3 in Fig. 1; and Fig. 4 is an elevational view in perspective of the seal element alone.

Referring to the drawings, in which like characters of reference denote corresponding parts, the reference character 10 indicates a watch case having a tubular neck 11 projecting exteriorly from its periphery.

The watch crown structure, according to this invention, comprises a suitably shaped hollow crown body 12 having a downwardly projecting axial shank 13 extending from its top wall, and a peripheral skirt wall 14 concentric to said shank, thus defining a downwardly open annular chamber 15 intermediate said shank and skirt wall. Within the upper interior of the chamber 15 is formed an internal annular shoulder 16, which is outwardly spaced from the shank 13 in concentric relation thereto.

The shank 13 is of external diameter substantially corresponding to the internal diameter of the watch case neck 11, so as to enter downwardly into said neck when the crown is operatively assembled therewith so that the neck enters upwardly into the crown chamber 15.

If the crown body 12 is produced from a base metal, as is ordinarily the case, an external shell 17 of relatively precious metal is applied over the exterior surface of said crown body, and the peripheral portions of said shell can be provided with finger engageable knurling or grooving 18, as shown, if desired.

The shank 13 of the crown body is provided with an internally screw-threaded, axially aligned socket 19 which enters thereinto from its bottom free end, and into which is threaded a winding and setting stem 20 which is adapted to be actuated by rotative manipulation of the crown.

The seal element of the crown structure is provided by a body of resilient material, such as soft natural or synthetic rubber or other resilient plastic material. The seal element comprises an axially extending tubular section 21 having an external annular supporting flange 22 projecting outwardly from its upper end, and from which it depends. The external diameter of said supporting flange 22 substantially corresponds to the internal diameter of the crown body chamber 15 which is defined by the skirt wall 14 of said crown body. The tubular section 21 of the seal element is provided with a bore 23, the internal diameter of which is somewhat less than the external diameter of the watch case neck 11. At its upper end, said bore 23 is preferably outwardly flared or divergently inclined, as at 24, in extension across the juncture of the tubular section 21 with the external annular supporting flange 22, thus reducing the thickness of the seal body at the point of conjunction of said tubular section with said external annular supporting flange, and thereby providing a relatively easily flexing portion 25 by which the former is joined to the latter, while at the same time spacing the inner periphery of the supporting flange outwardly from and thus out of contact with the neck 11 of the watch case 10.

In assembling the seal element in operative relation to the crown body, the same is entered upwardly through the open bottom of the latter into the chamber 15, so that the supporting flange 22 thereof abuts and seats upon the internal shoulder 16 within said chamber. To retain the seal element in such operative assembled relation to the crown body, a retainer ring 26 is provided. The external diameter of this retainer ring 26 is such as to make strong press fit with the internal surface of the crown body skirt wall 14 when driven into the crown chamber 15, whereby to be firmly attached thereto against outward displacement therefrom. It will be understood that the retainer ring may be nflixed in place within the crown chamber in any other known manner or by other fastening means. When thus entered in the crown body, said retainer ring 26 engages the under side of the supporting flange 22 of the seal element, so as to firmly grip the latter between the same and the internal shoulder 16 of the crown body, thereby firmly aflixing the seal ele- 3 ment in operative assembled relation to the crown body. Due to the fact that the innerperiphery of the supporting flange 22 of the seal element is outwardly spaced, by its flared-connection 24--with-'the tubular section 21, there tainer ring 26 can engage" said supporting flange with compressional force suflicientto assure clamping grip thereofbetweenthe shoulder 16 and said retainer ring, without causing anyfrictional contact ofthe compressed flange 22'with the watch case neck 11. The internaldiameter of the retainer'ring 26 is substantially greater than. the external diameter of the tubular section 21 of the seal element which extends downwardly therethrough; thusproviding an annular space27 between said tubular section and said-retainerring which therefore permits unimpeded flexing or outwardly yielding or what may be termed breathing? movement of said tubular section 21 of the seal-element inuse.

To assemble the crown in operative relation to the watch case 10, the shank 13 of the crown body 12 is slid down intothe interior of the watch case=neck 11, and is threaded onto the, winding and setting steme20 of the watch. As the crown is thus moved into assembledrelation to the watch case neck 11, the latter will. be caused to telescope upwardly into the bore 23 of the seal element, and since said bore is only sufliciently' smaller in diameter than the external diameter of the watch case neck to assure close fit against the latter, the tubular seal element will elastically embrace said neck'so as to effectively seal against the same, but without setting up undue frictional resistance to rotative movement of the seal element relative to said neck, since the pressure exerted is only that due to limited elastic constriction of said tubular section 21, and to flexing tension of the joint portion 25 of the seal element by which said tubular section is suspended from the supporting, flange 22.

of the seal element. Under these conditions the sealing tubular section 21 of the seal element is free to flex or. yield outwardly, that is to say to breathe, under the thrust of the watch case neck, when the seal element is rotated against said neck by manual turning of the crown By reason of this, friction tending to impede manual rotation of the crown is both reduced to a minimum and is easily overcome, and yet the sealing fit and contact of the tubular section 21 of the seal elemeht with the watch case neck is effectively maintained, especially under the normal stationary condition of the crown relative to the watch case neck.

Having now described my invention, I claim:

A waterproof winding stem: actuating crown for a watch case having, a projecting. neck about which the crown is rotatable comprising a downwardly open crown body'having: an internal, axial shank to which a winding stem is connectedwhen saidshankisventered' in the watch case neck, the crown body having within its upper interior an annular shoulder concentric to the shank and watch case neck in outwardly-spaced relation to the latter, a seal element of resilient material comprising a tubular sealing section having an outwardly projecting annular supporting flange integral with the upper end portion thereof and adapted'to. seat. upon said crown body shoulder, whereby said tubularsealing: section depends therefrom in surrounding sealing'contact with: the watch case neck, said tubular sealing'section having an internal outwardlyflared portion adjacent to its juncture with said supporting flange, whereby to. space the inner periphery of said supporting flange. outwardly from and out of contact with the watch case neck, while at the same time providingtarelativelyeasily flexing connection of reducedthicknessbetween said supporting flange and said. tubular sealingsection, and a retainer ring secured within the crown body so as to clamp said supporting flangeof: the seal element against-said crown body shoulder, the internal diameter of the retainer ring being greater than the external diameter. of the tubular sealing section of the sealing element, whereby the latter is free for yielding-movement in response to thrust of the watch case neck when the crown is turned about the latter.

References Cited in the file of this patent UNITED STATES PATENTS 2,405,087- Boninchi July 30, 1946 2,692,155 Gheen et al Oct. 19, 1954 is t 

